1. Field of the Invention
Embodiments of the invention relate to a solar cell.
2. Description of the Related Art
Recently, as existing energy sources such as petroleum and coal are expected to be depleted, interests in alternative energy sources for replacing the existing energy sources are increasing. Among the alternative energy sources, solar cells have been particularly spotlighted as cells for generating electric energy from solar energy, because the solar cells are able to draw energy from an abundant source and do not cause environmental pollution.
A solar cell generally includes a substrate and an emitter region, which are formed of a semiconductor of different conductive types, for example, a p-type and an n-type, and electrodes respectively connected to the substrate and the emitter region. A p-n junction is formed at an interface between the substrate and the emitter region.
When light is incident on the solar cell, a plurality of electron-hole pairs are generated in the semiconductors. The electron-hole pairs are separated into electrons and holes. Then, the separated electrons move to the n-type semiconductor (e.g., the emitter region), and the separated holes move to the p-type semiconductor (e.g., the substrate). The electrons and holes are collected by the electrodes electrically connected to the emitter region and the substrate, respectively. The electrodes are connected to each other using electric wires to thereby obtain electric power.